Middle cerebral artery thrombus susceptibility-weighted imaging mapping predicts prognosis

Susceptibility weighted imaging and mapping (SWIM) of magnetic resonance imaging (MRI) is used to evaluate cerebral arterial thrombosis. The aim of this research was to assess susceptibility, length, and clot burden score (CBS) of thrombus in the middle cerebral artery (MCA) and their relationship with cerebral infarction and early clinical prognosis in patients with acute or subacute cerebral infarction.

In total, 56 patients with acute or subacute cerebral infarction (with the time from onset to admission less than 72 h) and only unilateral MCA occlusion were included in the current study. All the patients had the corresponding susceptibility vessel sign (SVS) on susceptibility-weighted imaging (SWI). Parameters including susceptibility, length, and CBS of thrombus were obtained from SWI and SWIM. The differences in susceptibility of different portions of the thrombus were compared with each other by one-way ANOVA test. The relationship between susceptibility and stroke onset time was further analyzed by Spearman correlation analysis, in addition to the relationships between susceptibility, length, CBS, diffusion-weighted imaging-Alberta stroke program early CT score (DWI-ASPECTS), and admission and discharge National Institutes of Health Stroke Scale (NIHSS).

The susceptibility among different portions and different segments of thrombus showed no statistical difference. The susceptibility and length were weakly yet negatively correlated with DWI-ASPECTS (r_s=-0.382, -0.457; P=0.004, 0.000). The susceptibility was weakly yet positively correlated with admission NIHSS and discharged NIHSS (r_s=0.403, 0.430; P=0.002, 0.001). CBS was weakly yet positively correlated with DWI-ASPECTS (r_s=0.349; P=0.008) and weakly yet negatively correlated with admission and discharged NIHSS (r_s=-0.375, -0.335; P=0.004, 0.012).

The susceptibility remained consistent regardless of location, length, and onset time, which indicates that the thrombus composition was similar when detected on SWI less than 72 h from the onset. Susceptibility and CBS may help to predict clinical severity and short-term clinical prognosis to some extent.